feat(lotus-sim): print info on SIGUSR1

cmd/lotus-sim/info.go

@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"fmt"
+	"io"
 	"text/tabwriter"
 	"time"
 
@@ -13,6 +14,7 @@ import (
 	"github.com/filecoin-project/lotus/chain/actors/builtin/power"
 	"github.com/filecoin-project/lotus/chain/stmgr"
 	"github.com/filecoin-project/lotus/chain/types"
+	"github.com/filecoin-project/lotus/cmd/lotus-sim/simulation"
 )
 
 func getTotalPower(ctx context.Context, sm *stmgr.StateManager, ts *types.TipSet) (power.Claim, error) {
@@ -27,32 +29,18 @@ func getTotalPower(ctx context.Context, sm *stmgr.StateManager, ts *types.TipSet
 	return state.TotalPower()
 }
 
-var infoSimCommand = &cli.Command{
+func printInfo(ctx context.Context, sim *simulation.Simulation, out io.Writer) error {
-	Name:        "info",
+	powerNow, err := getTotalPower(ctx, sim.StateManager, sim.GetHead())
-	Description: "Output information about the simulation.",
-	Action: func(cctx *cli.Context) error {
-		node, err := open(cctx)
 	if err != nil {
 		return err
 	}
-		defer node.Close()
+	powerStart, err := getTotalPower(ctx, sim.StateManager, sim.GetStart())
-
-		sim, err := node.LoadSim(cctx.Context, cctx.String("simulation"))
-		if err != nil {
-			return err
-		}
-
-		powerNow, err := getTotalPower(cctx.Context, sim.StateManager, sim.GetHead())
-		if err != nil {
-			return err
-		}
-		powerStart, err := getTotalPower(cctx.Context, sim.StateManager, sim.GetStart())
 	if err != nil {
 		return err
 	}
 	powerGrowth := big.Sub(powerNow.RawBytePower, powerStart.RawBytePower)
 
-		tw := tabwriter.NewWriter(cctx.App.Writer, 8, 8, 0, ' ', 0)
+	tw := tabwriter.NewWriter(out, 8, 8, 1, ' ', 0)
 
 	head := sim.GetHead()
 	start := sim.GetStart()
@@ -81,5 +69,22 @@ var infoSimCommand = &cli.Command{
 	fmt.Fprintf(tw, "Power Growth Rate:\t%s/day\n", types.SizeStr(growthRate))
 	fmt.Fprintf(tw, "Network Version:\t%d\n", sim.GetNetworkVersion())
 	return tw.Flush()
+}
+
+var infoSimCommand = &cli.Command{
+	Name:        "info",
+	Description: "Output information about the simulation.",
+	Action: func(cctx *cli.Context) error {
+		node, err := open(cctx)
+		if err != nil {
+			return err
+		}
+		defer node.Close()
+
+		sim, err := node.LoadSim(cctx.Context, cctx.String("simulation"))
+		if err != nil {
+			return err
+		}
+		return printInfo(cctx.Context, sim, cctx.App.Writer)
 	},
 }

cmd/lotus-sim/run.go

@@ -2,6 +2,8 @@ package main
 
 import (
 	"fmt"
+	"os"
+	"os/signal"
 	"syscall"
 
 	"github.com/urfave/cli/v2"
@@ -36,12 +38,29 @@ var runSimCommand = &cli.Command{
 		}
 		fmt.Fprintln(cctx.App.Writer, "running simulation")
 		targetEpochs := cctx.Int("epochs")
+
+		ch := make(chan os.Signal, 1)
+		signal.Notify(ch, syscall.SIGUSR1)
+		defer signal.Stop(ch)
+
 		for i := 0; targetEpochs == 0 || i < targetEpochs; i++ {
 			ts, err := sim.Step(cctx.Context)
 			if err != nil {
 				return err
 			}
+
 			fmt.Fprintf(cctx.App.Writer, "advanced to %d %s\n", ts.Height(), ts.Key())
+
+			// Print
+			select {
+			case <-ch:
+				if err := printInfo(cctx.Context, sim, cctx.App.Writer); err != nil {
+					fmt.Fprintf(cctx.App.ErrWriter, "ERROR: failed to print info: %s\n", err)
+				}
+			case <-cctx.Context.Done():
+				return cctx.Err()
+			default:
+			}
 		}
 		fmt.Fprintln(cctx.App.Writer, "simulation done")
 		return err